It was just one voice at
first, loud and male, coming from the ceiling, saying, "Hi, John,"
calling him by name as if they were buddies. But after a while, the
voice, which he came to know as the "evil genius," urged him to steal
other people's brain cells and told him that he had a cancerous tumor
in his head.

Eventually, other voices
joined in, maybe 50 of them, male and female, yelling "as loud as
humans with megaphones," John recalled, from the moment he awoke in
the morning until he fell asleep at night, cursing or ordering him
to kill himself or, once, when he picked up a ringing telephone, screaming
in chorus, "You're guilty! You're guilty!"

"It was utter despair,"
John said. "I felt scared. They were always around."

Auditory hallucinations
are a hallmark of schizophrenia: 50 percent to 75 percent of the 2.8
million Americans who suffer from the illness hear voices that are
not there. Like John, whose schizophrenia was diagnosed in 1981 and
who spoke on the condition that he not be identified, many people
with schizophrenia spend years pursued by verbal tormentors as relentless
as the furies of Greek mythology.Suicide
is sometimes the result, death seeming the only escape from unending
harassment.

Yet psychiatrists who study
schizophrenia have traditionally shown little interest in the voices
their patients hear, often dismissing them as simply a byproduct of
the illness, "crazy talk" not worthy of study.

Recently, however, a small
group of scientists has begun studying auditory hallucinations more
intensively. Aided by new brain imaging techniques, they have begun
tracking such hallucinations back to abnormalities in the brain, finding
that certain brain regions "light up" on brain scans when patients
are actively hallucinating. And the experts are listening far more
carefully to what patients say about their hallucinatory experiences.

The research has led to
new theories of what may cause such bizarre alterations in perception
and has spawned at least one promising new treatment: the delivery
of low-frequency magnetic pulses to areas identified by the brain
scans seems to quiet, at least temporarily, the voices of patients
who have not found relief through standard treatment with antipsychotic
medications.

Ultimately, the researchers
say, knowing more about what causes auditory hallucinations may help
them understand more broadly the mechanisms that underlie schizophrenia
and other psychotic illness.

"These are critical, core
experiences that really constitute what having schizophrenia is all
about," said Dr. Ralph Hoffman, a psychiatrist at Yale who is studying
the magnetic stimulation treatment, called transcranial magnetic stimulation
or T.M.S.

In research described in
a recent issue of Archives of General Psychiatry, Dr. Hoffman and
his colleagues found that schizophrenic patients who received 132
minutes of the magnetic stimulation over 9 days showed a significant
reduction in auditory hallucinations compared with control subjects
given a dummy treatment. Half of the subjects in the study experienced
a return of their symptoms within 12 weeks, though in some cases,
the hallucinations remained at bay for up to a year. All the patients
were also taking antipsychotic medication.

Schizophrenic patients
describe voices that not only talk to them but talk about them, haranguing,
insulting and sometimes provoking them to hurt themselves or to perform
other actions. In many cases, the hallucinations become more intense
when the patient is under stress.

In a study of 200 patients
with schizophrenia and other psychotic illnesses, Dr. David L. Copolov,
director of the Mental Health Research Institute of Victoria in Melbourne,
Australia, and his colleagues found that 74 percent said they heard
voices more than once a day. More than 80 percent described the voices
as "very real," rather than "dreamlike" or "imaginary," and 34 percent
experienced the voices as coming from outside their heads (38 percent
said they came from both inside and outside their heads and 28 percent
from inside only).

A small minority of the
patients said the voices they heard were always or almost always supportive
and positive in tone. But more than 70 percent described them as always
or almost always negative. Dr. Hoffman of Yale said some of his research
subjects heard voices intermittently, but others heard them continuously,
the only respite coming when they slept. One patient who committed
suicide described her voices as "a constant state of mental rape,"
Dr. Hoffman said.

Nicole Gilbert, 37, received
a diagnosis of schizophrenia in 1985. For years, she said, she could
not read anything because her voices "would tell me that it was about
me." "They would say things to try to make me believe that I was Jesus,"
she recalled.

"Then they would torture
me and say: `We're just joking. You're so stupid, how could you believe
this?' "

Ms. Gilbert, who is much
recovered and is now a case manager at a mental health agency in California,
said the voices seemed so real that she could not believe it when
her friends told her she was hallucinating.

The findings of studies
using brain scanning techniques like positron emission tomography
(PET) or functional magnetic resonance imaging (M.R.I.) underscore
how persuasive auditory hallucinations are to those who experience
them. When patients are hallucinating, areas of the brain involved
with auditory perception, speech, emotion and memory show increased
blood flow, indicating greater nerve cell activity.

"These people are not just
crazy; they're telling you what their brains are telling them," said
Dr. David Silbersweig, an associate professor of psychiatry at Weill
Medical College of Cornell University who has studied hallucinations
with brain-imaging. Still, studies so far have come up with differing
patterns of brain activation. For example, both Dr. Hoffman's group
and a team led by Dr. Philip McGuire, a professor at the Institute
of Psychiatry in London, found heightened activity in Broca's area,
a region of the frontal lobe involved with speech perception and processing.
But Broca's area was not identified in Dr. Silbersweig's research
or in a study by Dr. Copolov that will be published soon. The precise
areas of the brain's temporal and parietal lobes that show activity
during hallucinations also differ from study to study.

The discrepancies are difficult
to interpret and reflect the imprecision of even advanced technology
in capturing highly complex brain processes. The data are further
clouded because the high costs of scans limit the size of most studies.

But the disparity in the
findings has also led to different theories about how hallucinations
arise.

Schizophrenia typically
strikes in adolescence or early adulthood. Extensive research over
the last few decades has indicated that the brains of people with
the illness differ in significant ways from those of healthy people.
Experts agree that schizophrenia stems from a combination of genetic
predisposition and unknown environmental influences. What everyone
who studies hallucinations agrees on is that schizophrenic patients
misperceive signals generated inside the brain.

But scientists are still
debating what is being misinterpreted and how this occurs. Dr. Copolov,
for example, suggests that the "voices" patients hear are really fragments
of auditory memories "that come to consciousness fused with emotional
content" and are then incorrectly evaluated as originating from an
outside source.

The fact that in some studies
the hippocampus and other brain structures known to be involved in
memory retrieval are active during hallucinations is consistent with
this theory, Dr. Copolov said. Other researchers, including Dr. McGuire
of the London institute, have argued that what is misperceived is
internal speech - the running dialogue most people engage in while
thinking. In schizophrenia, in this view, a mechanism that normally
distinguishes between internal and external speech breaks down.

Dr. Judith Ford, an associate
professor of psychiatry at Stanford, and Dr. Daniel Mathalon, an assistant
professor of psychiatry at Yale, have proposed that the brain's auditory
cortex may play a role in this failure to identify speech correctly
as internal or external. In studies, they recorded electrical activity
in the auditory cortices of schizophrenic patients and healthy control
subjects. In the control group, the auditory cortex showed a dampening
of activity in response to internal speech, they found. But this inhibition
was lacking in schizophrenic patients.

"When you and I have these
thoughts," Dr. Ford said, "we are inhibiting the response of our auditory
cortex, saying, `Don't pay attention to this; it's me, talking.' But
the schizophrenic patients do not inhibit the response the way normal
healthy people do."

Dr. Hoffman has a slightly
different theory. In schizophrenia, he suggests, a loss of gray matter
may intensify the link between Broca's area, involved in speech production,
and Wernicke's area, responsible for speech perception.

In the normal course of
affairs, Dr. Hoffman said, Wernicke's area receives information from
a variety of nearby brain areas and distant structures like Broca's.
But in schizophrenic patients, who in imaging studies show a loss
of gray matter in the superior temporal lobe containing Wernicke's,
the signals sent from more local regions may be knocked out or greatly
decreased. If so, Dr. Hoffman suggests, the signals coming from Broca's
may then become more salient, bombarding Wernicke's area with internally
generated words and phrases that are in some way interpreted by Wernicke's
as external speech.

Dr. Hoffman noted that
transcranial magnetic stimulation applied to Wernicke's area appeared
to suppress hallucinations in some schizophrenics. "My view is that
in schizophrenia it is not just inner speech or an acoustic memory
that is misinterpreted," Dr. Hoffman said. Instead, he said, patients
"are actually having perceptual experiences that have the same clarity
and vividness of external speech."

Dr. Hoffman's research
team is now using M.R.I. scanning with each research subject to determine
which brain regions are active when the subject is hallucinating,
and then delivering stimulation to that area.

But whatever the research
on magnetic stimulation yields, it is already helping some of the
25 percent of hallucinating patients whose voices are not stopped
by antipsychotic drugs.

"Just stimulating in a
single site appears to have a significant impact," Dr. Hoffman said.

Other experts call the
results impressive.

In the treatment, an electromagnetic
coil shaped like a Figure 8 is held to the patient's head. The coil
produces a quarter-size magnetic field that is then rapidly turned
on and off, inducing an electrical field in the cerebral cortex's
gray matter. Scientists do not know exactly how the treatment works,
but they believe it dampens the reactivity of neurons, an effect that
is then passed on to other connected brain regions.

Unlike electroshock therapy,
long used for severe depression, transcranial magnetic stimulation
does not induce seizures at the levels used in the studies and has
a far more selective effect on the brain. Nor does the treatment appear
to have the serious side effects, like memory loss, of electroshock
therapy.

The most common side effect,
Dr. Hoffman said, is mild contractions of the scalp that some patients
find uncomfortable. Also, in contrast to electroshock, patients receiving
the magnetic stimulation remain awake, unsedated, through it. John,
who participated in Dr. Hoffman's research last summer, said the procedure
did not bother him. "This thing kind of taps on your head every second
and it's not intrusive," John said. He said his voices got "smaller
and not as loud" after treatment, but they did not go away entirely,
and the improvement lasted only six months.

Without a full cure in
sight, John said he has developing his own tactics for fighting the
hallucinations, which persist despite the medications he takes. He
talks back to them in his head, he said, and criticizes them when
they criticize him. Between his own efforts and the treatments, John
has made much progress. He now attends school, has his own apartment,
goes out with friends and has a girlfriend. "I wanted to try to make
the voices my friends, but I found out later that that is not realistic,"
John said. "I was kicked around by them for a long time. Now, if they
start bothering me, I just kick them around instead."